Elemental oxygen occurs predominantly in form of a covalent homodimer on, that is a compound of two O2 atoms and having the empirical formula O2, referred to as molecular oxygen or dioxygen. There is a colorless and odorless gas that is contained in air to 20.942%. It is involved in many combustion and corrosion processes (oxygen for energy).
An older method is based on chemical reactions barium oxide method. It is uneconomical due to high energy costs. For barium oxide is heated under air at 500 degrees C., the barium forms. When heated to 700 degrees C recorded earlier O2 is released by thermolysis again. Prior to development of Linde process, this method was the only way to pure O2 present.
From the Stone Age to Middle Ages, the fire to humans was a phenomenon which has been accepted as a gift from heaven. About the nature of fire caused by the different conceptions natural philosophers of antiquity to alchemist. The fire was seen as an essential ingredient of Earth. In 17th century the notion of a "light mysterious substance" was born. This phlogiston would escape from the burning fuel, heat was understood as a substance. The German-Swedish chemist Carl Wilhelm Scheele conducted experiments. When heating manganese dioxide (manganese dioxide) or potassium permanganate with concentrated sulfuric acid (vitriol) he gave a colorless gas.
O2 is slightly soluble in water. The solubility depends on the pressure and the temperature. It increases with decreasing temperature and increasing pressure. At 0 degrees C and an O2 partial pressure of air of 212 hPa dissolve in pure water 14.16 mg / l oxygen. In oxygen-gas discharge Spectrum, the molecular orbitals of O2 are stimulated to emit light. The operating conditions are a pressure of 5-10 mbar, a high voltage of 1.8 kV, a current of 18 mA and a frequency of 35 kHz. During the recombination of ionized gas molecules, the characteristic color spectrum is emitted. In this case, a small part, caused reversibly formed by the supply of energy ozone.
With the discovery of O2 its meaning was not clear during combustion. The Frenchman Antoine Lavoisier found in his experiments that during combustion does not escape phlogiston, but O2 is bound. By weighing it demonstrated that a substance after combustion was not easier but harder. This was caused by the additional weight of ingested during the combustion process oxygen.
Initially, the O2 has been accepted as a basic component for the formation of acids. Therefore, the term Oxygenium (acidifier) 1779 proposed by Lavoisier oxygen. In fact, most inorganic acids in solution of non-metal oxides in O2 water. The halogens, such as chlorine and bromine, is therefore held for a long time oxides of unknown elements. Only later was recognized that hydrogen is responsible for the acid character.
Occupation of energy levels of molecular orbitals of O2 in ground and excited states. In ground state the spins of two valence electrons of Hund's rule are arranged in parallel in obedience. It is a triplet state with the term symbol 3g. It is the state with the lowest energy. Through the two unpaired electrons, the two orbitals are half occupied. This caused some characteristic properties, such as the diradical character and the paramagnetism of O2 molecule.
Usually takes O2 in its compounds, and in earth before. In earth's crust almost all minerals and rocks are so well oxygenated water next. Among the most important minerals include oxygen-containing silicates such as feldspars, mica and Olivine, carbonates such as calcium carbonate in limestone and oxides such as silica as quartz.
An older method is based on chemical reactions barium oxide method. It is uneconomical due to high energy costs. For barium oxide is heated under air at 500 degrees C., the barium forms. When heated to 700 degrees C recorded earlier O2 is released by thermolysis again. Prior to development of Linde process, this method was the only way to pure O2 present.
From the Stone Age to Middle Ages, the fire to humans was a phenomenon which has been accepted as a gift from heaven. About the nature of fire caused by the different conceptions natural philosophers of antiquity to alchemist. The fire was seen as an essential ingredient of Earth. In 17th century the notion of a "light mysterious substance" was born. This phlogiston would escape from the burning fuel, heat was understood as a substance. The German-Swedish chemist Carl Wilhelm Scheele conducted experiments. When heating manganese dioxide (manganese dioxide) or potassium permanganate with concentrated sulfuric acid (vitriol) he gave a colorless gas.
O2 is slightly soluble in water. The solubility depends on the pressure and the temperature. It increases with decreasing temperature and increasing pressure. At 0 degrees C and an O2 partial pressure of air of 212 hPa dissolve in pure water 14.16 mg / l oxygen. In oxygen-gas discharge Spectrum, the molecular orbitals of O2 are stimulated to emit light. The operating conditions are a pressure of 5-10 mbar, a high voltage of 1.8 kV, a current of 18 mA and a frequency of 35 kHz. During the recombination of ionized gas molecules, the characteristic color spectrum is emitted. In this case, a small part, caused reversibly formed by the supply of energy ozone.
With the discovery of O2 its meaning was not clear during combustion. The Frenchman Antoine Lavoisier found in his experiments that during combustion does not escape phlogiston, but O2 is bound. By weighing it demonstrated that a substance after combustion was not easier but harder. This was caused by the additional weight of ingested during the combustion process oxygen.
Initially, the O2 has been accepted as a basic component for the formation of acids. Therefore, the term Oxygenium (acidifier) 1779 proposed by Lavoisier oxygen. In fact, most inorganic acids in solution of non-metal oxides in O2 water. The halogens, such as chlorine and bromine, is therefore held for a long time oxides of unknown elements. Only later was recognized that hydrogen is responsible for the acid character.
Occupation of energy levels of molecular orbitals of O2 in ground and excited states. In ground state the spins of two valence electrons of Hund's rule are arranged in parallel in obedience. It is a triplet state with the term symbol 3g. It is the state with the lowest energy. Through the two unpaired electrons, the two orbitals are half occupied. This caused some characteristic properties, such as the diradical character and the paramagnetism of O2 molecule.
Usually takes O2 in its compounds, and in earth before. In earth's crust almost all minerals and rocks are so well oxygenated water next. Among the most important minerals include oxygen-containing silicates such as feldspars, mica and Olivine, carbonates such as calcium carbonate in limestone and oxides such as silica as quartz.
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